What is the difference between speed and velocity? If you are a physics student, you must be familiar with these two terms. For those who are still coming across this term, they might seem the same as they are both related to the rate at which an object is moving. That said, there are big differences between them and we will be telling you here.
Before we give the key differences between these two physics terms, let us start first by defining them.
What is speed?
Speed is a scalar quantity that refers to how fast an object is moving. It is the distance traveled by an object per unit of time, without regard to direction. The formula for speed is:
speed = distance ÷ time
where distance is the distance traveled by the object, and time is the duration of the travel.
Speed can be expressed in a variety of units depending on the context, such as meters per second (m/s), kilometers per hour (km/h), or miles per hour (mph). The unit of speed depends on the units used for distance and time.
It’s important to note that speed only tells us how fast an object is moving, but it doesn’t provide any information about the direction of its motion. To fully describe an object’s motion, we need to use velocity, which is a vector quantity that includes both speed and direction.
Velocity
Velocity is a vector quantity that refers to how fast an object is moving in a particular direction. It is the rate at which an object changes its position, with both magnitude and direction included. The formula for velocity is:
velocity = displacement ÷ time
where displacement is the change in the position of the object, and time is the duration of the change.
Velocity is expressed in units of distance per unit of time, with direction included. For example, if an object is moving north at a speed of 10 meters per second, its velocity would be 10 meters per second north (10 m/s N).
It’s important to note that velocity is not the same as speed, which only describes how fast an object is moving without regard to direction. Velocity provides a more complete description of an object’s motion since it includes both the magnitude of the speed and the direction of the object’s motion.
What is the difference between speed and velocity?
Speed and velocity both describe the rate at which an object is moving, but they are not the same thing.
Speed is a scalar quantity that refers to the distance traveled by an object per unit of time. It is the magnitude of the velocity vector and is always positive. Speed is expressed in units of distance per unit of time, such as meters per second (m/s), kilometers per hour (km/h), or miles per hour (mph).
Velocity is a vector quantity that refers to the displacement of an object per unit of time, with direction included. It is the rate at which an object changes its position. Velocity includes both the magnitude of the speed and the direction of the object’s motion. Velocity is expressed in units of distance per unit of time with direction, such as meters per second east (m/s E), or kilometers per hour north (km/h N).
| Speed | Velocity |
|---|---|
| A scalar quantity | A vector quantity |
| Cannot be negative or zero | Velocity can be zero, negative, or positive. |
| Average speed will continue to count even if the object changes direction | Changes with the change in direction, therefore the object must follow one direction. |
| Speed may or may not be equal to the velocity | An object may possess different velocities but the same speed |
In summary, speed describes how fast an object is moving, while velocity describes how fast an object is moving in a particular direction.
